Your lock screen is useful for all sorts of things, like contact info or emergency numbers, but if you have something you need to memorize, your lock screen is the perfect place to put it—after all, you see it all the time. Not only will you be able to check that schedule really quickly, but seeing it every time you turn on your phone will help burn it into your brain. Apartment Therapy offers a number of other suggestions, like memorizing your new city's subway system, a chart or reference you need to memorize, and more. It may not make for the most attractive lock screen, but when you need to memorize something quickly, it can be immensely useful.